Corresponding Author

Competing Interests

David Osrin is on the Editorial Board of PLoS Medicine.

Author Contributions

ICMJE criteria for authorship read and met: ZM AAC SN DO NM WS. Agree with the manuscript's results and conclusions: ZM AAC SN DO NM WS. Designed the experiments/the study: ZM. Analyzed the data: AAC. Wrote the first draft of the paper: ZM AAC. Contributed to the writing of the paper: AAC SN DO NM WS. Organised the paper, co-ordinated contributions and finalised last draft: ZM. Review and analysis of existing literature: SN. Critically revised the manuscript for content: WS.